Electronic devices that serve a variety of functions, such as smartphone, tablet PCs, etc. have proliferated.
In recent years, electronic devices have been developed to provide functions of user authentication by using the biometric information of the user. For example, fingerprint, iris scan, etc. have been used. In other use cases, biometric information, for example, heartrate, is detected and recorded to manage the user's health.
There are various ways in which a biometric sensor may sense biometric information. For example, the biometric information of the user may be detected by shining light, such as infrared and visible light, onto the body of the user and detecting the light reflected by the body.
However, when biometric information is sensed by using light rays, portions of the emitted light rays may be refracted so that they are not incident on the body of the user. Similarly, portions of the reflected light rays may not be incident on the biometric sensor. In these cases, efficiency of the biometric sensor is reduced. Also, in these cases, noises in the biometric signal may increase.